It might have been short-lived, but Charlie Puth says his fling with Selena Gomez really took a toll on him.

Speaking with Billboard, the “Attention” singer opened up about that time in his life. “It’s about a particular moment in my life when someone very close to me wanted the ‘attention’ of somebody else,” Puth, 26, said. “When I found that out and we ended it, I might have done some shady things too, and she might have asked me, ‘How long has this been going on?'”

Still playing coy, Puth hinted that both tracks, “Attention” and “How Long”, were inspired by Gomez and Justin Bieber’s on-and-off relationship. “I don’t kiss and tell, but the only way a song like that can come across as real is if there’s something else going on behind the scenes. And that’s what was happening. Very short-lived, very small, but very impactful. And it really messed me up. I’m trying to put this the best way possible: It wasn’t like I was the only person on her mind,” Puth explained. “And I think I knew that going in… what I was getting myself into.”

While admitting “Attention” isn’t a particularly nice song, Puth says he realizes its impact on his career.

“It’s s**t-talking. It’s a mean song,” he continued. “I didn’t feel like an artist until ‘Attention’ came out. And I feel like people are just starting to get it. I’m not mad that they’re just finding out – they’re getting the message I wasn’t allowed to say before. ‘Attention’ is me saying, ‘F**k everybody: I’m doing this song the way I want to do it.'”